This article was originally published in http://www.stuff.co.nz/sport/rugby/opinion/83867218/what-nz-rugby-understands-about-concussion-and-what-it-wants-to-find-out
The issue of concussion in contact sport has rightly received a great deal of focus over the past few years. When New Zealand Rugby and World Rugby approached AUT (Auckland University of Technology) in 2012 to commission a study of retired rugby players, research examining health issues among former sportspeople was largely limited to American Football. We’re now seeing a range of research being carried out across many sports.
At the time the project was intended to involve data from 600 former players using web-based data collection, and 75 former players using laboratory based data collection. Recruitment was difficult at the time. Given increased media, player and public awareness of concussion issues, recruitment would likely be much easier if the study was conducted now.
Players’ health outcomes were compared for 100 professional rugby players, 195 community rugby players and 65 non-contact elite sports players, with the potential impact of head injuries and long-term health outcomes being one focus of the study.
AUT’s experience and world-leading research techniques were invaluable. Participants in the study undertook a variety of tests, including the CNSVS (Central Nervous System Vital Signs) test . This test is designed to be used in conjunction with a neuropsychologist’s clinical assessment.
However, it can be used to examine how well groups of people are performing compared to each other and a normative sample from the United States, and as a triage tool to refer people for further evaluation. People who complete the CNSVS test would need to be formally assessed by a neuropsychologist to gain individual feedback of the meaning of the results.
The type of study design we used can’t show causality, partly because we don’t know whether, or to what extent, the groups of players differed on the measures we used to examine cognitive functions before they played sport. While the differences identified between players who suffered repeated concussions and those who didn’t are concerning and require closer examination, the effects on the whole were small. Scientifically we need to remain circumspect about how confident we can be that the differences we observed will hold among other study groups, or exist in the wider population.
A single study rarely provides definitive answers to the research question at hand – science tends to work in a cumulative manner. Although we study samples of people, and look at the effect in the sample, what we need to know is whether the effect exists in the wider population. We use statistical techniques to help make inferences about the likelihood of the effect actually being present beyond the study group. The results of multiple studies build an evidence base upon which people can have increasing confidence that the effect being studied is likely to exist beyond the sample groups that have been studied. The AUT researchers, and NZ Rugby, are working independently with other groups internationally to gather more evidence.
Keeping an open mind scientifically is a different thing from not accepting the potential implications of the study. Both World Rugby and NZ Rugby have recognised that there is a potential link between playing contact sport and some forms of dementia for a number of years, and are acting according to the ‘precautionary principle’. In other words, even though we don’t know for sure whether such a relationship exists based on the available scientific evidence, we are acting as though it does. We are trying to manage and minimise risks associated with concussions by raising public awareness of the injury, implementing injury management practices that reduce risk, and conducting further research into the issue. As evidence continues to emerge, we will continue to take all reasonable steps to protect the health and well-being of participants.
What we know from the NZ RugbyHealth study is that it met its aims of describing areas of potential benefit or concern. It was envisaged that the “snap-shot” in time of the study design would provide information that could be used to design prospective studies. The NZ RugbyHealth study has been an important first step in our understanding more about the likely long term effects of playing rugby.
So, in conclusion, while it doesn’t look like playing rugby is associated with profound impacts on cognitive function in general, former players as a group performed slightly worse than non-contact players on several of the tests used. In addition, slightly more players than would have been expected if there were no issues, scored at very low levels on some variables. The important next stage is to do the responsible thing and find out more about the issue, including, for example, whether dementia rates among former players differ from those among non-players. While rugby is already working on this, we’re not alone in doing so. Increased research, increased education and increased focus to remove the risks of head knocks in contact sports around the world will benefit us all.
New Zealand Rugby Senior Scientist